Optical encoding detecting coarse and fine position

摘要

An optical type encoder is comprised of a gauge member and a sensor portion moved relative to each other with the movement of an object to be detected. The gauge member has a plurality of slit rows comprising a plurality of slits formed at intervals along the direction of movement of the object to be detected, and a plurality of slit intervals formed by the corresponding slits in the slit rows are made partly equal. The sensor portion has at locations corresponding to the slit rows position detecting type light receiving means for receiving light beams from light projecting means passed through the plurality of slits rows of the gauge member, and the position information of the object to be detected is detected by the utilization of signals from these light receiving means.